Bob R

Dukes Gear Actuator Gears

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First, I will say this has probably been asked and answered, so I apologize. Just looked at my actuator gears and they have to be replaced. Was looking on Maxwell's site and if I am reading them correctly,  they charge $800 for the gear set and $818 for the seals and such? Can that be correct? I looks like I can get a set of 20:1 gears for less than $500. Can someone put me back on the right track? Also, if a shop actually has to do the work, although reading the AD it does not look like rocket science, anyone know a decent shop outside of Lasar? I certainly do no want to go back there after they broke my artificial horizon and never did repair it.

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I'm not sure 20:1 gears are legal to install? You want 40:1. Call Maxwell and find out what it would take for the job.

Sent from my LG-US996 using Tapatalk

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19 minutes ago, KSMooniac said:

I'm not sure 20:1 gears are legal to install? You want 40:1. Call Maxwell and find out what it would take for the job.

Sent from my LG-US996 using Tapatalk
 

From what I can gather the 20: and gears are still legal as they're still being sold. The point I'm trying to make is why spend $1600 plus the cost to install them if I could just swap out the gears for $500. The cost savings pays for a lot of 200 hour checks and since those gears that are in mine now have been in there for $3,000 just don't see a big issue. Seems nobody's even sure if the newer style gears remove the AD or not. OBVIOUSLY I'M LOOKING FOR THE COST-BENEFIT ANALYSIS OF THIS.

 

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You really want the 40:1 gears. If you had them you wouldn't be replacing them now. 

There are also two types of 40:1 gears. There was a service bulletin to take them out of service. The earlier 40:1 gears had a steel worm and a steel ring. The newer gears have a steel worm and a brass ring.

I have about 1500 hours on the new gears and they show no wear at all. I also have a new set of the steel gears that I got on eBay for $20. They are still legal, but they have a shorter inspection interval. I'm keeping them as a backup. 

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5 minutes ago, N201MKTurbo said:

You really want the 40:1 gears. If you had them you wouldn't be replacing them now. 

There are also two types of 40:1 gears. There was a service bulletin to take them out of service. The earlier 40:1 gears had a steel worm and a steel ring. The newer gears have a steel worm and a brass ring.

I have about 1500 hours on the new gears and they show no wear at all. I also have a new set of the steel gears that I got on eBay for $20. They are still legal, but they have a shorter inspection interval. I'm keeping them as a backup. 

Steel against brass? I'm not an alchemist but still being a hard metal and brass being a soft metal I don't think your gear is brass. I can see the logic in the 40 to 1 gears as the gear will come down slower and it won't be so abrupt. My issue is what happens with the ad does anybody really know? In addition, if I have to $1600+ in parts to gain 300 hours on the interval, I'm not sure it's worth it. The actuator in this airplane  as I understand it, is underpowered and was meant to be a Cessna flap actuator.

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On 8/3/2019 at 2:08 PM, N201MKTurbo said:

You really want the 40:1 gears. If you had them you wouldn't be replacing them now. 

I struggle greatly with that statement.  My gears will eventually need to be replaced, but they've served me and prior owners well for thousands of hours.  Frankly, I don't care if the new 40:1 gears will last 100,000 hours... I'm unlikely to put enough hours on the plane to care.  And, as far as future buyers; if they walk because I have the 'old' 20:1 gears, I'll count myself lucky not to deal with a buyer that picky!

Honestly, I like how fast my gear goes up and down:D

I know what I'd do if the decision was $500 in parts vs. $1600!

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On 8/3/2019 at 2:49 PM, Bob R said:

First, I will say this has probably been asked and answered, so I apologize. Just looked at my actuator gears and they have to be replaced. Was looking on Maxwell's site and if I am reading them correctly,  they charge $800 for the gear set and $818 for the seals and such? Can that be correct? I looks like I can get a set of 20:1 gears for less than $500. Can someone put me back on the right track? Also, if a shop actually has to do the work, although reading the AD it does not look like rocket science, anyone know a decent shop outside of Lasar? I certainly do no want to go back there after they broke my artificial horizon and never did repair it.

I think that based on the statement from SI M20-112 you could argue a longer interval with your FSDO.

OPTIONAL RETROFIT KIT - Compliance to this Service Instruction M20-112 revises 200 hour inspection of the gears specified in service Bulletin M20-190B. The inspection interval is now per instructions as outlined in Mooney Service and Maintenance Manual for M20J serial numbers 24-0001 thru 24-0377. (reference MAC M20J service maintenance manual section 5-20-06) actuator gear inspection is now: After 500 hours of operation and then every 200 hours thereafter.

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1 hour ago, MikeOH said:

I struggle greatly with that statement.  My gears will eventually need to be replaced, but they've served me and prior owners well for thousands of hours.  Frankly, I don't care if the new 40:1 gears will last 100,000 hours... I'm unlikely to put enough hours on the plane to care.  And, as far as future buyers; if they walk because I have the 'old' 20:1 gears, I'll count myself lucky not to deal with a buyer that picky!

Honestly, I like how fast my gear goes up and down:D

I know what I'd do if the decision was $500 in parts vs. $1600!

That is pretty much where my decision will be based since the airframe just hit 4000 hours and the gears just wore out. If the cost for the new gear set is in fact $1600 for the two gears, (5), yes 5, 2/1000" shims, a bearing and a seal, that's crap  Just the cost difference of approximately $300 between the 20:1 and 40:1 ratio gears is a huge rip off. The gear sets cost the same to produce. Grade 8 steel and grade 8 steel is the same thing. IMHO, at a minimum, Mooney should be supplying parts at their cost. Heck, for that matter, I should go to the local boneyard and I'm positive I can find the exact actuator from a Cessna which used them for flaps. FAA is the monster here and they could continually allow this to happen. By the way, outside of overhauling the actuator motor, installing either set of gears takes just a general level of mechanical ability and a 6th grade education. I can't wait to see what the shop will quote just to install the gears. Should take about 30 minutes.

I will post the quotes even if they come with KY jelly.

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59 minutes ago, Bob R said:

...

I will post the quotes even if they come with KY jelly.

Hmm, me thinks they will come with 80 grit:o

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1 hour ago, Bob R said:

That is pretty much where my decision will be based since the airframe just hit 4000 hours and the gears just wore out. If the cost for the new gear set is in fact $1600 for the two gears, (5), yes 5, 2/1000" shims, a bearing and a seal, that's crap  Just the cost difference of approximately $300 between the 20:1 and 40:1 ratio gears is a huge rip off. The gear sets cost the same to produce. Grade 8 steel and grade 8 steel is the same thing. IMHO, at a minimum, Mooney should be supplying parts at their cost. Heck, for that matter, I should go to the local boneyard and I'm positive I can find the exact actuator from a Cessna which used them for flaps. FAA is the monster here and they could continually allow this to happen. By the way, outside of overhauling the actuator motor, installing either set of gears takes just a general level of mechanical ability and a 6th grade education. I can't wait to see what the shop will quote just to install the gears. Should take about 30 minutes.

I will post the quotes even if they come with KY jelly.

Why don’t you have your maintainer install a set of gears?  If you can find a set of 20:1 gears and he can read the service documents available on the Mooney website he can do it.

Clarence

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Buy the gears and have your AP sign off.  No it is not that hard.  The SB should serve as the proper data, since you don't have the actuator manual.   Technically I believe it was a Cessna Jet flap actuator.   Don't let your motor end up in California for a rebuild or your Emergency disconnect will suddenly become "unserviceable".   Brass seems suspect Bronze seems more probable.   Bronze bushings are in lots of things.

Edited by Yetti

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Hi Everyone,

I am going to pilot produce the 40:1 gears. I replaced my 20:1 gears with a 20:1 set from the local bone yard which showed no wear. My AP was just fine with it. I just believe the price that Mooney wants for the 40:1 gears is ludicrous and nothing short of rape without even using KY. Hell, I might have my buddy make the gears out of Titanium as even Ti would be cheaper than Mooney gears. If we do them out of steel, Grade 8 Steel is Grade 8 Steel. At present, he is making me a new door handle right now. Who knows, he just may make it out of Ti. He also 3D printed me a couple of sets of rear seat back release levers. I have a set if someone needs a set. Work perfectly.

Bob

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1 hour ago, Bob R said:

Hi Everyone,

I am going to pilot produce the 40:1 gears. I replaced my 20:1 gears with a 20:1 set from the local bone yard which showed no wear. My AP was just fine with it. I just believe the price that Mooney wants for the 40:1 gears is ludicrous and nothing short of rape without even using KY. Hell, I might have my buddy make the gears out of Titanium as even Ti would be cheaper than Mooney gears. If we do them out of steel, Grade 8 Steel is Grade 8 Steel. At present, he is making me a new door handle right now. Who knows, he just may make it out of Ti. He also 3D printed me a couple of sets of rear seat back release levers. I have a set if someone needs a set. Work perfectly.

Bob

I like the way you think!

However, (there's always a 'however')...my understanding is that there needs to be acceptable data to back up the owner produced parts; in this case precision gears.  How are you planning to satisfy the FAA on that one?  (I'm pretty sure Mooney isn't going to release their engineering drawings to you so that you can reproduce their criminally overpriced ones!)

I have no doubt that you can produce adequate gears but without the proper paperwork I'd be concerned about my insurance coverage in the event there is EVER a problem with the gear extending.  Say, the next owner has an accident with injuries after he is forced to land gear up/partially extended?  How is that going to play out?

I'm just paranoid enough of our sadly litigious society that I'm going to buy the 20:1 approved gears like you just did.

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Hi Everyone,
I am going to pilot produce the 40:1 gears. I replaced my 20:1 gears with a 20:1 set from the local bone yard which showed no wear. My AP was just fine with it. I just believe the price that Mooney wants for the 40:1 gears is ludicrous and nothing short of rape without even using KY. Hell, I might have my buddy make the gears out of Titanium as even Ti would be cheaper than Mooney gears. If we do them out of steel, Grade 8 Steel is Grade 8 Steel. At present, he is making me a new door handle right now. Who knows, he just may make it out of Ti. He also 3D printed me a couple of sets of rear seat back release levers. I have a set if someone needs a set. Work perfectly.
Bob

In the end, owner produced parts need only be approved by AP, so what does your AP say?


Tom

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Just now, ArtVandelay said:


In the end, owner produced parts need only be approved by AP, so what does your AP say?


Tom

Is that really true?

I honestly thought you needed to have some kind of backup technical data to support the owner produced part??

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39 minutes ago, ArtVandelay said:

From your link, I believe the concerning part is the following excerpt:

"In completing the Form 337, the A&P/IA must cer- tify that the owner-produced part conforms to FAA-approved data. As a general rule, this means either the owner-produced part was made from a manufacturer-approved drawing, or it was made by duplicating an existing approved part and therefore all materials and dimensions can be determined from the existing part. If the A&P/IA has any doubts about whether or not the part conforms to approved data, he may choose to ask the local flight standards dis- trict office for a field approval of the repair (which could delay return of the aircraft to service) or require that a designated engineering representative be hired to generate the necessary approved data."

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From your link, I believe the concerning part is the following excerpt:
"In completing the Form 337, the A&P/IA must cer- tify that the owner-produced part conforms to FAA-approved data. As a general rule, this means either the owner-produced part was made from a manufacturer-approved drawing, or it was made by duplicating an existing approved part and therefore all materials and dimensions can be determined from the existing part. If the A&P/IA has any doubts about whether or not the part conforms to approved data, he may choose to ask the local flight standards dis- trict office for a field approval of the repair (which could delay return of the aircraft to service) or require that a designated engineering representative be hired to generate the necessary approved data."

That’s why I said to talk to your AP, he may require it be made of the same metal as the original. I love Titanium but there be consequences (for example it’s too hard and accelerates wear of other gears or has a different expansion rate so it binds if extremely cold, etc). You can’t be sure of unintentional consequences without a thorough analysis.
Personally I don’t see a real upside of changing the metal used, I would just duplicate it.


Tom
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2 hours ago, ArtVandelay said:


That’s why I said to talk to your AP, he may require it be made of the same metal as the original. I love Titanium but there be consequences (for example it’s too hard and accelerates wear of other gears or has a different expansion rate so it binds if extremely cold, etc). You can’t be sure of unintentional consequences without a thorough analysis.
Personally I don’t see a real upside of changing the metal used, I would just duplicate it.


Tom

Oh, I completely agree with that!  Changing the metal used would be a seriously big deal to justify to the FAA, IMHO.

More from your link on that point: 

"However, the mechanic still needs to ensure that the owner-produced part conforms to the aircraft type design, which may be easy or difficult depending on what kind of part is involved."

I'd think making new gears could present a pretty difficult challenge; how do you even know what kind of steel was used without the factory drawing?  Heat treating? Case or through hardened? Gear profiles and tolerances, end play, ...all kinds of critical stuff to properly duplicate.  Sure, you can theoretically reverse engineer, but at what cost to provide adequate data that your work is accurate and complete?  This isn't duplicating a wing skin where the proper material is clearly called out in the parts manual.

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On 12/28/2019 at 2:50 PM, ArtVandelay said:


In the end, owner produced parts need only be approved by AP, so what does your AP say?


Tom

I'll ask him. I doubt he will have an issue with it. Will let you know when I see him.

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On 8/4/2019 at 8:37 PM, Yetti said:

Buy the gears and have your AP sign off.  No it is not that hard.  The SB should serve as the proper data, since you don't have the actuator manual.   Technically I believe it was a Cessna Jet flap actuator.   Don't let your motor end up in California for a rebuild or your Emergency disconnect will suddenly become "unserviceable".   Brass seems suspect Bronze seems more probable.   Bronze bushings are in lots of things.

I just may have bought the $4000 + gear set had it not been a 4 month lead time from the time I ordered them. Even Lasar had no idea when they would come in. Therefore, I found a better way. Not sure why you would think 20:1 gears would cause the motor to have to be rebuilt. 20:1 is 3 seconds up and 3 seconds down. 40:1 is 6 seconds up and 6 seconds down. Less motor time with 20:1 and I am thinking the motor is actually spinning less with the current gear set vs. the newer sets. I could be wrong though.

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I had been to Longview and Maxwell converted my 20:1 gear to 40:1 with the Mooney retrofit kit. Afterwards the old electric  gear motor did not want to work anymore. He converted the gear back to the old one and the motor was running fine again. I took the uninstalled kit home.

I kept it like this for a while and then my local A+P/IA removed the actuator with the motor and sent it to Lasar. They got the motor overhauled and replaced the gears again with my kit from Maxwell. Now everything is working fine.

The gear in the actuator is a very small worm which has to hold a good amount of pressure during the gear cycle. If you have the 6 seconds new gear, the force to the gear is less and it will last longer.

It is not written in the Service Instruction, but Maxwell said that the gear down speed may increase because of the modification tp 40:1. Reason is that you have the same setup as the early M20J which also have a higher gear speed then my M20F.  But you may not want to do it because 1) it is not written down somewhere and 2) the higher gear speed will again put more pressure and wear on the actuator. 

I have been told that a motor with worn out brushes .... may work better with the old 20:1 actuator. 

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Remember that failure of these gears(owner produced with no accurate specifications) can leave you with no way to lower the gear.  The Mooney manual extension system relies on the same gear set as the electric motor.

Clarence

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While it would be fairly straight forward to machine a set of these gears, install them and verify that they are running well. There has been 3 if not 4 different sets of materials used in these gears to get to the current material which lasts almost forever. It isn't easy to accurately determine which steel and heat treat was used and what yellow metal was used.

If you do choose to produce your own parts, I would start with a 50 hour inspection interval until you determine weather they will last.

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